Typical inductive motors include an active set of multiphase windings coupled to the stator and an inactive (or reactive) set of multiphase windings coupled to the rotor. A multiphase power signal is applied to the active set of multiphase windings. The electrical current produced by the multiphase power signal in the active set of windings produces a magnetic field that results in an opposite current in the inactive set of multiphase windings. The opposite current results in an opposing magnetic field that causes the rotor to turn. As the rotor turns, the opposite current within the inactive set of multiphase windings decreases, reducing the magnetic field. The motor eventually settles at an equilibrium speed based on a load attached to the motor and a frequency of the multiphase power signal. The equilibrium speed is generally a frequency that is slightly less than the frequency of the AC power signal. The difference between the frequency of the AC power signal and the rotational frequency of the rotor is known as a slip frequency (or slip angle). In typical systems with a constant load, both the rotational frequency of the rotor and the slip angle are dependent on the frequency of the AC power signal.
In order to achieve an independent rotational frequency, typical motor systems may rely on a rectifier circuit to perform a full-power AC to DC power conversion, then an inverter to perform another full-power DC to AC power conversion with the new AC power signal having the desired frequency, magnitude, and phase. The new AC power signal can then be used to drive an induction motor at the corresponding new frequency. This full-scale power conversion may result significant power losses. Further, the components required to perform the power conversion may add significant weight, which may be undesirable in particular applications, such as within aircraft.